DuckDB / MotherDuck MCP server

Run DuckDB SQL from an agent over local files, in-memory data, S3 or MotherDuck — good for quick analysis of CSV, Parquet and JSON without a warehouse.

Install

Claude Code — local DuckDB file, read-only

claude mcp add --scope user duckdb --transport stdio -- uvx mcp-server-motherduck@1.0.8 --db-path /absolute/path/to/db.duckdb

Claude Code — in-memory scratch database
```
claude mcp add --scope user duckdb --transport stdio -- uvx mcp-server-motherduck@1.0.8 --db-path :memory: --read-write --allow-switch-databases
```
The vendor's "dev mode". No guardrails — it can read and write local files and switch to any database.
Claude Desktop

One-click .mcpb bundle from the repo's latest release.

MotherDuck’s local MCP server for DuckDB. Five tools: execute_query, list_databases, list_tables, list_columns, and (if enabled) switch_database_connection. DuckDB reads CSV, Parquet and JSON directly from disk or S3, which makes this a fast way to let an agent explore an export or a data dump.

When to use it

Ad-hoc analysis of files on your machine without loading them into a warehouse.
Prototyping queries before they go into dbt or a production pipeline.
Querying a MotherDuck cloud database from your editor.

Before you install

Since v1.0 the server is read-only by default for files and MotherDuck; --read-write turns writes on. In-memory databases are always writable. MotherDuck in read-only mode needs a read-scaling token. Don’t expose the HTTP transport to other people — MotherDuck recommends its hosted Remote MCP for that, or SaaS mode plus --init-sql hardening if you self-host.

Official

Published by the platform or the maker of the thing itself.

Access: Reads your accounts Connects to a service or data source and changes nothing.
Review: Reviewed — install with care
Scan: 100/100 SkillSpector 2.12.0 said do not install at 275d2e7
Checked: Sep 25, 2026

1 CRITICAL and 25 HIGH, all read. The CRITICAL and three HIGHs are advisories on pinned dependencies in uv.lock (anyio, joserfc, mcp). "Credential access" hits are the MotherDuck token CLI option, .env in ignore files and test fixtures, and "keyring" package names in uv.lock. The agent-config hits are README rows naming where Codex and Gemini keep MCP config. "os.environ.copy()" is only in e2e tests. The server makes no network calls of its own beyond DuckDB and MotherDuck connections. CAUTION because it runs agent-written SQL, and DuckDB SQL can read and write local files. The README warns that read-only mode alone doesn't stop filesystem access.

Publisher: MotherDuck
Source: github.com/motherduckdb/mcp-server-motherduck
Works with: Claude apps, Claude Code, Codex, Gemini, Cursor, Any agent
Categories: Data & analytics, MCP & integrations, Databases & warehouses
License: MIT
Cost: Free

Curated by Andrew Borden-Chisholm. Notes on building with these tools are on the blog.